Generally, a shallow trench isolation (STI) may be formed by initially forming a trench within a substrate. The trench may then be lined with, e.g., an oxide liner formed by chemical vapor deposition (CVD). The oxide liner may then be etched in order to reduce the STI aspect ratio and widen the STI opening, which facilitate a subsequent gap fill process. Once the oxide liner is at the desired thickness and profile, the trench may be filled and overfilled with dielectric material before being planarized such that the dielectric material is planar with the substrate, thereby forming the STI.
However, as semiconductor devices have gotten smaller and smaller in the never ending race to miniaturize, problems have arisen with this process as semiconductor devices have shrunk to the twenty-eight nanometer node and smaller. In particular, as the trenches have been miniaturized to meet the twenty-eight nanometer node, a gel like material has begun to be formed during the manufacturing of the STIs, creating defects in some of the STIs that are being manufactured. Additionally, the defects caused by the gel like material are persistent and are not removed by an aging process.
In an effort to fix this problem of gelation, various treatments have been attempted to treat the gel like material. For example, a sulfuric peroxide mixture (SPM) has been applied to the gel like material in an attempt to react and remove the gel like material. Additionally, in an attempt to improve over the simple SPM process, an oxygen ashing process has also been utilized in conjunction with the SPM process. However, neither of these processes has been sufficient to remove the defects. Additionally, both of these processes only treat the gel like material after it has been formed, and do not address or treat the underlying causes of the creation of the gel like material.
Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated. The figures are drawn to clearly illustrate the relevant aspects of the embodiments and are not necessarily drawn to scale.